Divisible tooth



April l1, i933- R. H. @ILLE-SPIE DIVISIBLE TOOTH Filed July l, 1924 j? fj GLLESPE Patented pr. 11,` 1933 PArEr ROBERT EAMTLTON GILLESPIE, OF LITTLE ROCK, ARKANSAS, ASSIGNOR '.10 THE COLUMBUS DENTAL MANUFACTURING CMPANY, OF COLUMBUS, OHIO,

TION

A CORPORA- DIVISIBLE TOOTH This invention relates to dentistry, and specifically to an improved divisible tooth. One object of the invention is to provide an improved form of tooth-body which can be attached to removable bridges or dentures,

vand which is provided with means for detachably securing a cusp on the tooth, whereby the cusp can be removed for the purpose of obtaining anatomical occlusion.

`Another object is to provide an improved tooth-body (of porcelain or other suitable material) with a removable metal backing having thereon a bitingl surface and being adapted for use on artificial dentures or removable bridges; whereby, the said metal backing can be covered with inlay wax after the tooth-body has been vulcanized or otherwise attached. to the denture or removable bridge, a bite or impression then taken from they occludent tooth While the work is in the patients mouth, and thereby obtaining anatomical occlusion in said inlay wax; and whereby the metal backing can then be removed from said tooth-body together with said bite or impression thereon to form a mould into which the cusp can be cast of gold or other metal; and whereby the backing (and its metal cusp) can then be replaced and secured on the said tooth-body, thus completing the process of forming the artificial tooth.

Another object is to provide an improved removable artificial tooth-facing body for fixed bridge-work, that permits the bridge to be soldered or cast while separated from the tooth-body, and then permits the toothbody to be replaced on the bridge.

Another object is to provide an improved tooth-body that can be removed from the bridge and replaced on the bridge without removing the bridge from the patients mouth.

Another object is to provide an improved artificial tooth-facing or body that can be removed from the bridge for the purpose of baking porcelain on the gingival end thereof and thus making it longer so its gingival end will fit the outer convex of the gums, or fit the tooth-socket of the gums.

Another object is to provide an improved tooth comprising a tooth-body of porcelain (orthe like), and a metal cusp or biting surface, so arranged that the metal cusp is held out of contact with the gums, and only the porcelain or non-metallic part of the tooth comes into contact with the gums.

Another object is to provide an improved tooth-body of porcelain (or the like) removably interlocked with a metal plate including a biting surface on which wax may be secured; whereby a bite or impression can be made in the wax while the tooth-body and plate are interlocked and in theV patients mouth, thereby obtaining anatomical occlusion; and whereby said tooth body can be removed from the metal plate lwhile the cusp is being cast or otherwise secured on the meta-l plate. a

Another object is to provide a divisible tooth having its dividing joint formed of two evenly curved surfaces slidable against one another while each is conforming to the shape of the other, and including a curved locking joint; whereby these separable parts of the tooth have the maximum strength and rigidity in consequence of their curved interlocking parts; and whereby, if either of these parts is iixed in position, the other part can be removed with comparative ease in consequence of the arcuate movement necessary in moving such part out of locked engagement with the lixed part.

Other objects and important features will be pointed out or implied in the following detailsk of description, in connection with the accompanying drawing in which:

Fig. l is a greatly enlarged vertical sectional view, the section being in a central plane through and longitudinally of the interlocking rib and channel, of the backing or cusp-plate and tooth-body, respectively. Fig. 2 is a vertical sectional view of the tooth shown in Fig. 1, the section being in a plane at right angles to that of Fig. 1.

Fig. 3 is a sectional view in the same plane as Fig. 1, but only the porcelain tooth-body being here shown; this figure being a slightly modified form in that its gingival end is formed with a concave surface. Fig. 4 is a vertical sectional view of a modified form of .within the tooth body;

the invention, the lower part of the toothbody and of the securing element being broken olf. Fig. 5 is a side view and rear view of the backing plate and securing member shown in Fig. 4.

Referring to the drawing in detail, in which similar reference characters correspond to similar parts throughout the several views:

The tooth-bodies 10, 10;L and 10b are preferably formed of porcelain or other suitable non-metallic substance; and is formed with an evenly curved concave surface 11 and a channel 12 or 12b. The channel 12 has an even longitudinal curvature and a substantially uniform cross section. The channel 412" includes a straight and substantially horizontal bore (Fig. 7), and a vertical slot 12c which is of non-uniform depth because it opens into and intersects the forwardly and upwardly inclined surface 11. Each of these channels has its front end terminating but its rear or inner end is open through the rear or inner surface of the tooth-body, thus permitting entrance and exit of a rib which is of a shape and size to fit snugly in the channels 12 and 12b, respectively, and to be slid into and out of the respective channels, for the purposes specilied in the foregoing paragraphs. The rib 13 is united with a plate, herein referred to as a backing or cusp-plate, and its convex surface, which adjoins the rib 13, is of the same even curvature as the surface 11 of the tooth-body, so these respective convex and concave surfaces lit snugly and slide smoothly on one another, only sufiicient micrometric space being allowed between the contiguous surfaces of the parts at this joint to accommodate a suitable cement or adhesive substance for securing the tooth-body and cuspplate to one another, against accidental seperation; such securing material being preferably adapted to soften at a temperature slightly above that of the hottest food that a person can take into the mouth, so that the tooth-body and cusp-plate can be separated with comparative lease by the proper application of heat thereto.

The cusp 1,5 may be formed of gold or any suitable material, and may be either formed integrally with the cusp-plate or secured thereto by any appropriate means. In Fig. 1, the cusp-plate and its rib are indicated in broken lines in position to be slid into place on the tooth-body. The element 15, in Figures 1 and 2, may be considered either as permanent cusps, or temporary cusps of wax after the bite or impression has been made by the occludent tooth.

The convex gingival ends of the teeth such as shown in Figures 1 and 2 are for fitting into a gums-socket, and the concave gingival end 16 of Figure 3 is to i'it against the convex surface of the gums. lVhen the toothvcylindrical part of the rib body 10ZL is removed from a fixed bridge, it slides forward and upward (now considering lower bridge-work), as indicated by the broken-line position of Fig. 3, at the same time tilting at each point of its path of movement until the interlocking parts 12 and 13 are disengaged from one another. The parallel lines, at the bottom of Fig. 3, show the extent of elevation for a slight lateral movement. This tilting relieves suction of the concave part against the gums and avoids unnecessary discomfort to the patent.

Inremovable bridge-work, the cusp-plates are preferably separate from one another, so they can be removed, individually, from the respective tooth-bodies. In the fixed bridge-worlnthe tooth-bodies are removable, individually, from the respective ribs of the cusp-plates.

In the form shown in Figs. 4 and 5, the cusp plate 14 diverges with respect to the 13b, the direction of divergence being from rear to front of the tooth; so, in this form, the cusp plate does not slide on the surface 11 while the cylinder of the rib 13" slides into and out of the rear part of the bore of the groove or cavity 12b; but this divergence permits the cusp-plate to have a minute sliding and wedging action on the surface 11 when the part 13bhas approximately` reached its forwardmost position when being seated, thus assuring an extremely snug lit of the cuspplate on its seat 11.

In the form shown in Figs. 4 and 5, the cusp-plate is formed with a biting edgeportion or tip 1G having a substantially plane seating surface which is upwardly and forwardly inclined, but more nearly level than the adjoining convex part of the cusp-plate. A correspondingly plane and inclined surface is formed on the crown of thetoothbody, serving as a seatfor the biting tip. It is to be understood that the concave surface of the cusp-plate 14b is to receive the cusp, as described in the foregoing, but the part 16 remains exposed to provide a metal biting edge at the front of the tooth-crown.

Each rib 13 and 13 comprises a plate and a cylinder, the diameter of the cylinder being .greater than the thickness of the plate; and,

since the channels or cavities 12 and 12" are, respectively, the same size and shape of the ribs that lit in them, they combine with the ribs to form interlocking connections which have the same functionand mode of connecting and disconnecting as those of the well known dovetail connection. Therefore, the ribs will hereinafter be defined as equivalents of d'ovetailed tenons, and the grooves or cavities will be defined as equivalents of do'vetailed mortises.

Either form of the invention, as shown in Figs. 1, 2, 3, 4, and 5, is applicable to either removable or fixed bridgework.

It is not intended to limit this invention to the exact construction and arrangement here shown, but changes may be made within the scope of the inventive ideas as implied and claimed.

`What I claim as my invention is:

l. lIhe divisible tooth which includes a tooth-body and a cusp-plate; the tooth-body being formed with a forwardly and upwardly inclined surface, a slot intersecting said surface and being open through the rear side of the tooth-body, and a cylindrical bore through said rear surface and extending forward and being in open communication with said slot; the said bore being substantially horizontal, so it is in diverging relation to said forwardly and upwardly inclined surface; said cusp-plate being provided with a cylindrical part to slide and fit in said bore, and a plate to slide and fit in said slot, this plate being thinner than the diameter of said cylinder and serving tounite the latter with the cusp-plate in such relation that the cuspplate fits on said upwardly inclined surface when the said plate and cylinder are fitting in said slot and bore.

2. rlhe structure defined by claim l, said cusp-plate and its seat on said tooth-body being curved, for the purpose specified.

3. A divisible tooth which includes a tooth body having a root extension and a cusp plate; the crown portion being formed with a labio-occlusally inclined surface, a substantially triangular slot intersecting said surface, a niortise wider than said slot opening rearwardly and being in open communication with said slot, the said mortise being substantially horizontal and in diverging relation to the part of the labio-occlusally inclined surface intersected by the slot; said cusp plate being provided with a tenon to slide and fit in said mortise, and a plate to slide and fit in said slot, said plate being thinner than said tenon and serving to unite the latter with the cusp plate in such relation that the cusp plate fits on said inclined surface when said plate and tenon are fitted in said slot and mortise.

4. An artificial tooth comprising a toothbody having an inclined occlusally directed end surface provided with an undercut recess directed forwardly in angular relation to said surface, and a cusp structure arranged to support said tooth body and having a similarly directed inclined surface provided with means arranged to so interlock with said recess as to tend to maintain said surfaces wedgedly engaged.

5. An artificial pontic tooth body having a root extension and having in its occlusally directed end surface an undercut socket comprising a slot7 terminating away from said surface in a broadened recess inclined with respect to said surface.

6. A divisible tooth including a tooth body and a cusp plate, the tooth body being formed with an integral root extension, a backing seat formed on said tooth body, said seat being disposed so as to be out of contact with the gum, a bore in the tooth body extending from the lingual face toward the labial face, a slot of less diameter opening said bore for a part of its length to the surface of said seat, the remaining portion of the bore being closed to said seat, and divergent to said surface, said cusp plate having a post connected to it by a plate of less diameter than the post whereby the post and plate are adapted to slide and fit in said bore and slot and thereby connect the cusp plate to the tooth body, the labial end portion of the post eXtendin into the tooth body beyond the labial end of the slot.

In testimony whereof I affix my signature.

ROBERT HAMILTON GILLESPIE. 

